Polymer and polymer electrolyte membrane comprising same

ABSTRACT

The present specification relates to a polymer with improved ion transport capability, a polymer electrolyte membrane including the same, a membrane-electrode assembly including the polymer electrolyte membrane, a fuel cell including the membrane-electrode assembly, and a redox flow battery including the polymer electrolyte membrane.

TECHNICAL FIELD

The present specification claims priority to and the benefit of KoreanPatent Application Nos. 10-2014-0173157, 10-2014-0173178,10-2014-0173137, and 10-2014-0173142 filed in the Korean IntellectualProperty Office on Dec. 4, 2014, the entire contents of which areincorporated herein by reference.

The present specification relates to a polymer and a polymer electrolytemembrane including the same.

BACKGROUND ART

A fuel cell is an energy conversion device that converts chemical energyof a fuel directly into electrical energy. That is, the fuel cell uses afuel gas and an oxidizing agent, and adopts a method of producingelectric power by using the electrons generated during the redoxreaction of the fuel gas and the oxidizing agent. A membrane-electrodeassembly (MEA) of the fuel cell is a part in which an electrochemicalreaction of hydrogen and oxygen occurs, and is composed of a cathode, ananode, and an electrolyte membrane, that is, an ion conductiveelectrolyte membrane.

A redox flow battery (oxidation-reduction flow battery) is anelectrochemical storage device that stores chemical energy of an activematerial directly into electrical energy by using a system in which theactive material included in an electrolytic solution is oxidized andreduced and thus the battery is charged and discharged. A unit cell ofthe redox flow battery includes an electrode, an electrolyte, and an ionexchange membrane (electrolyte membrane).

Fuel cells and redox flow batteries have been researched and developedas a next-generation energy source due to high energy efficiency andeco-friendly characteristics producing less emission of contaminants.

The most essential constituent element of the fuel cells and the redoxflow batteries is a polymer electrolyte membrane capable of exchangingcations, and the polymer electrolyte membrane may have characteristicsof 1) excellent proton conductivity, 2) prevention of crossover of theelectrolyte, 3) strong chemical resistance, 4) strengthening ofmechanical properties and/or 4) a low swelling ratio. The polymerelectrolyte membrane is classified into fluorine-based, partialfluorine-based, hydrocarbon-based, and the like, and the partialfluorine-based polymer electrolyte membrane has a fluorine-based mainchain, and thus has advantages in that physical and chemical stabilitiesare excellent and thermal stability is high. Further, the partialfluorine-based polymer electrolyte membrane has advantages of both ahydrocarbon-based polymer electrolyte membrane and a fluorine-basedpolymer electrolyte membrane because a cation transport functional groupis attached to the ends of a fluorine-based chain similarly to afluorine-based polymer electrolyte membrane.

However, the partial fluorine-based polymer electrolyte membrane has aproblem in that cation conductivity is relatively low because the microphase separation of the cation transport functional group and theaggregation phenomenon are not effectively controlled. Accordingly,studies have been conducted toward securing high cation conductivitythrough the distribution of sulfonic acid groups and the control of themicro phase separation.

CITATION LIST Patent Document

Korean Patent Application Laid-Open No. 10-2003-0076057

DETAILED DESCRIPTION OF THE INVENTION Technical Problem

The present specification has been made in an effort to provide apolymer having improved ion transport capability and a polymerelectrolyte membrane including the same.

Technical Solution

The present specification provides a polymer including: a first monomerrepresented by the following Chemical Formula 1; and

a second monomer which is different from the first monomer and has atleast one sulfonic acid group.

In Chemical Formula 1,

A is —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, —PO₃ ²⁻2M⁺,—O(CF₂)_(m)SO₃H, —O(CF₂)_(m)SO₃ ⁻M⁺, —O(CF₂)_(m)COOH, —O(CF₂)_(m)COO⁻M⁺,—O(CF₂)_(m)PO₃H₂, —O(CF₂)_(m)PO₃H⁻M⁺, or —O(CF₂)_(m)PO₃ ²⁻2M⁺,

m is an integer from 1 to 6,

M is a Group 1 element,

R1 and R2 are the same as or different from each other, and are eachindependently a halogen group,

n is an integer from 1 to 10, and

when m and n are 2 or more, two or more structures in the parenthesisare the same as or different from each other.

Further, the present specification provides a polymer electrolytemembrane including the polymer.

In addition, the present specification provides a reinforced membraneincluding: a substrate; and the polymer.

The present specification provides a membrane-electrode assemblyincluding: an anode; a cathode; and the above-described polymerelectrolyte membrane disposed between the anode and the cathode.

Further, the present specification provides a membrane-electrodeassembly including: an anode; a cathode; and the above-describedreinforced membrane disposed between the anode and the cathode.

The present specification provides a polymer electrolyte-type fuel cellincluding: the above-described two or more membrane-electrodeassemblies; a stack which includes a bipolar plate disposed between themembrane-electrode assemblies; a fuel supplying part which supplies fuelto the stack; and an oxidizing agent supplying part which supplies anoxidizing agent to the stack.

Further, the present specification provides a redox flow batteryincluding: a positive electrode cell including a positive electrode anda positive electrode electrolytic solution; a negative electrode cellincluding a negative electrode and a negative electrode electrolyticsolution; and the above-described polymer electrolyte membrane disposedbetween the positive electrode cell and the negative electrode cell.

Finally, the present specification provides a redox flow batteryincluding: a positive electrode cell including a positive electrode anda positive electrode electrolytic solution; a negative electrode cellincluding a negative electrode and a negative electrode electrolyticsolution; and the above-described reinforced membrane disposed betweenthe positive electrode cell and the negative electrode cell.

Advantageous Effects

A polymer electrolyte membrane including a polymer according to anexemplary embodiment of the present specification is advantageous informing a hydrophilic channel.

Further, for the polymer electrolyte membrane, a hydrophilic channel isefficiently formed in the polymer electrolyte membrane by controllingthe phase separation structure.

Furthermore, the polymer electrolyte membrane has excellent protonconductivity. Consequently, a high performance of a fuel cell and/or aredox flow battery including the same is brought about.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view illustrating the electricity generationprinciple of a fuel cell.

FIG. 2 is a view schematically illustrating an example of a redox flowbattery.

FIG. 3 is a view schematically illustrating an example of a fuel cell.

EXPLANATION OF REFERENCE NUMERALS AND SYMBOLS

-   -   100: Electrolyte membrane    -   200 a: Anode    -   200 b: Cathode    -   10, 20: Tank    -   11, 21: Pump    -   31: Electrolyte membrane    -   32: Positive electrode cell    -   33: Negative electrode cell    -   41: Positive electrode electrolytic solution    -   42: Negative electrode electrolytic solution    -   60: Stack    -   70: Oxidizing agent supplying part    -   80: Fuel supplying part    -   81: Fuel tank    -   82: Pump

BEST MODE

Hereinafter, the present specification will be described in more detail.

When one part “includes” one constituent element in the presentspecification, unless otherwise specifically described, this does notmean that another constituent element is excluded, but means thatanother constituent element may be further included.

An exemplary embodiment of the present specification provides a polymerincluding: the first monomer represented by Chemical Formula 1; and asecond monomer which is different from the first monomer and has atleast one sulfonic acid group.

In the present specification, the —[CR1R2]_(n)-A structure and an S atomas a linker of the benzene ring in Chemical Formula 1 are used. In thiscase, due to the electron withdrawing character of —[CR1R2]_(n)-A linkedwith the S atom, it is possible to provide a polymer which is easilyformed and is stable.

In an exemplary embodiment of the present specification, R1 and R2 arethe same as or different from each other, and are each independently ahalogen group. Specifically, R1 and R2 may be each independentlyselected from the group consisting of F; Cl; Br; and I.

When a polymer including the first monomer represented by ChemicalFormula 1 of the present specification is included in a polymerelectrolyte membrane, if R1 and R2 of Chemical Formula 1 are a halogengroup, electrons may be withdrawn well, so that the acidity of the Afunctional group is increased, and accordingly, there are advantages inthat the movement of hydrogen ions may be facilitated and the structureof the polymer electrolyte membrane may become strong. Specifically,according to an exemplary embodiment of the present specification, whenR1 and R2 are fluorine, the advantages may be maximized.

According to an exemplary embodiment of the present specification, R1and R2, which are substituted with carbon adjacent to A in ChemicalFormula 1, may serve to increase decationization.

In an exemplary embodiment of the present specification, by furtherincluding a second monomer which is different from the first monomer andhas at least one sulfonic acid group, it is possible to increase themaximum ion exchange capacity (IEC) of a polymer and to expect anincrease in ion conductivity. Accordingly, it is advantageous in forminga hydrophilic channel of a polymer electrolyte membrane including apolymer according to an exemplary embodiment of the presentspecification.

In an exemplary embodiment of the present specification, n is an integerfrom 2 to 10. In another exemplary embodiment of the presentspecification, n is an integer from 2 to 6.

The monomer represented by Chemical Formula 1 according to an exemplaryembodiment of the present specification may adjust the number of n's. Inthis case, the monomer may adjust the length of the structure in theparenthesis to serve to facilitate the phase separation phenomenon ofthe polymer electrolyte membrane, and to facilitate the movement ofhydrogen ions of the polymer electrolyte membrane.

In an exemplary embodiment of the present specification, n is 2.

In another exemplary embodiment, n is 3.

In still another exemplary embodiment, n is 4.

In yet another exemplary embodiment, n is 5.

In still yet another exemplary embodiment, n is 6.

In a further exemplary embodiment, n is 7.

In an exemplary embodiment of the present specification, n is 8.

In another exemplary embodiment, n is 9.

In an exemplary embodiment of the present specification, n is 10.

In an exemplary embodiment of the present specification, A is —SO₃H or—SO₃ ⁻M⁺.

In another exemplary embodiment, A is —SO₃H.

As described above, when A in Chemical Formula 1 is —SO₃H or —SO₃ ⁻M⁺, achemically stable polymer may be formed.

In an exemplary embodiment of the present specification, M is a Group 1element.

In the present specification, the Group 1 element may be Li, Na, or K.

In an exemplary embodiment of the present specification, the monomerrepresented by Chemical Formula 1 is represented by any one of thefollowing Chemical Formulae 1-1 to 1-9.

In an exemplary embodiment of the present specification, the secondmonomer is derived from a compound represented by the following ChemicalFormula 2 or Chemical Formula 3.

In Chemical Formulae 2 and 3,

A1 to A4 are the same as or different from each other, and are eachindependently a hydroxy group; or a halogen group,

L1 is a direct bond; CR3R4; C═O; O; S; SO₂; SiR5R6; or a substituted orunsubstituted fluorenylene group,

R3 to R6 are the same as or different from each other, and are eachindependently hydrogen; an alkyl group; fluorine; a haloalkyl group; ora phenyl group,

S1 to S3 are the same as or different from each other, and are eachindependently hydrogen; deuterium; a halogen group; a cyano group; anitrile group; a nitro group; a hydroxy group; a haloalkyl group; asulfonic acid group; a substituted or unsubstituted alkyl group; asubstituted or unsubstituted cycloalkyl group; a substituted orunsubstituted alkoxy group; a substituted or unsubstituted alkenylgroup; a substituted or unsubstituted silyl group; a substituted orunsubstituted aryl group; or a substituted or unsubstituted heterocyclicgroup,

s1, s2, and s3 are each an integer from 1 to 4,

m′ is an integer from 1 to 5,

when s1, s2, s3, and m′ are each an integer of 2 or more, two or morestructures in the parenthesis are the same as or different from eachother, and

Chemical Formula 2 and Chemical Formula 3 are substituted with at leastone sulfonic acid group.

In an exemplary embodiment of the present specification, A1 is a hydroxygroup.

In another exemplary embodiment, A1 is a halogen group.

In an exemplary embodiment of the present specification, A2 is a hydroxygroup.

In another exemplary embodiment, A2 is a halogen group.

In an exemplary embodiment of the present specification, L1 is SO₂.

In an exemplary embodiment of the present specification, the secondmonomer is derived from a compound represented by any one of thefollowing Chemical Formulae 2-1 to 2-4, 3-1, and 3-2.

In Chemical Formulae 2-2, 2-4, and 3-2,

A1′ and A2′ are the same as or different from each other, and are eachindependently a halogen group.

In an exemplary embodiment of the present specification, the secondmonomer may be selected from the following structures.

In the present specification, the halogen group is fluorine; chlorine;bromine; or iodine.

In the present specification, the “derived” means that a new bond isgenerated while the bond of a compound is broken, or a substituent isdetached, and a monomer derived from the compound may mean a repeatingunit which constitutes a polymer. The monomer may be included in a mainchain in a polymer to constitute the polymer.

Specifically, the “derived” means that the monomer is included in apolymer while hydrogen is detached or a halogen group is detached from asubstituted hydroxy group (—OH) in Chemical Formula 2 and ChemicalFormula 3, and constitutes a repeating unit, that is, a monomer.

In an exemplary embodiment of the present specification, the polymer mayfurther include a brancher. In the present specification, the brancherserves to link or cross-link polymer chains.

In the present specification, in the case of a polymer further includingthe brancher, the brancher may directly constitute a main chain of thepolymer, and may improve a degree of mechanical integrity of a thinfilm. For example, in a branched polymer of the present invention, abrancher directly constitutes a main chain of a polymer without carryingout a post-sulfonation reaction or a cross-linking reaction of asulfonated polymer by polymerizing a branched hydrophobic block whichdoes not include acid substituents and a branched hydrophilic blockwhich includes acid substituents, and a hydrophobic block whichmaintains a degree of mechanical integrity of a thin film and ahydrophilic block which imparts ion conductivity to a thin film mayalternately lead to chemical bonds.

In an exemplary embodiment of the present specification, the polymerfurther includes a brancher derived from a compound of the followingChemical Formula 4 or a brancher represented by the following ChemicalFormula 5.

In Chemical Formulae 4 and 5,

X is S; O; CO; SO; SO₂; NR; and a hydrocarbon-based or fluorine-basedbinder,

l is an integer from 0 to 100,

when l is 2 or more, two or more X's are the same as or different fromeach other,

Y1 and Y2 are the same as or different from each other, and are eachindependently NRR; an aromatic ring which is once or twice or moresubstituted with a substituent selected from the group consisting of ahydroxy group and a halogen group; or an aliphatic ring which is once ortwice or more substituted with a substituent selected from the groupconsisting of a hydroxy group and a halogen group,

R is an aromatic ring substituted with a halogen group; or an aliphaticring substituted with a halogen group, and

Z is a trivalent organic group.

Examples of the substituents in the present specification will bedescribed below, but are not limited thereto.

In the present specification,

means being bonded to an adjacent substituent or a main chain of apolymer.

In the present specification, a brancher derived from the compound ofChemical Formula 4 may serve as a brancher while in an aromatic ringsubstituted with a halogen group of each of Y1 and Y2; or an aliphaticring substituted with a halogen group, the halogen group is detachedfrom the aromatic ring or the aliphatic ring.

The term “substitution” means that a hydrogen atom bonded to a carbonatom of a compound is changed into another substituent, and a positionto be substituted is not limited as long as the position is a positionat which the hydrogen atom is substituted, that is, a position at whichthe substituent may be substituted, and when two or more aresubstituted, the two or more substituents may be the same as ordifferent from each other.

In the present specification, a hydrocarbon-based compound means anorganic compound composed only of carbon and hydrogen, and examplesthereof include a straight hydrocarbon, a branched hydrocarbon, and acyclic hydrocarbon, and the like, and are not limited thereto. Further,the hydrocarbon-based compound may include a single bond, a double bond,or a triple bond, and are not limited thereto.

In the present specification, a fluorine-based binder means that acarbon-hydrogen bond is partially or entirely substituted with fluorinein the hydrocarbon-based compound.

In the present specification, the aromatic ring may be an aromatichydrocarbon ring or an aromatic hetero ring, and may be monocyclic orpolycyclic.

Specific examples of the aromatic hydrocarbon ring include a monocyclicaromatic ring, such as a phenyl group, a biphenyl group, and a terphenylgroup, and a polycyclic aromatic ring, such as a naphthyl group, abinaphthyl group, an anthracenyl group, a phenanthrenyl group, a pyrenylgroup, a perylenyl group, a tetracenyl group, a chrysenyl group, afluorenyl group, an acenaphthacenyl group, a triphenylene group, and afluoranthene group, and the like, but are not limited thereto.

In the present specification, an aromatic hetero ring means a structureincluding one or more heteroatoms, for example, O, S, N, Se, and thelike instead of a carbon atom in the aromatic hydrocarbon ring. Specificexamples thereof include a thiophene group, a furan group, a pyrrolegroup, an imidazole group, a thiazole group, an oxazole group, anoxadiazole group, a triazole group, a pyridyl group, a bipyridyl group,a pyrimidyl group, a triazine group, a triazole group, an acridyl group,a pyridazine group, a pyrazinyl group, a qinolinyl group, a quinazolinegroup, a quinoxalinyl group, a phthalazinyl group, a pyridopyrimidinylgroup, a pyridopyrazinyl group, a pyrazinopyrazinyl group, anisoquinoline group, an indole group, a carbazole group, a benzoxazolegroup, a benzoimidazole group, a benzothiazole group, a benzocarbazolegroup, a benzothiophene group, a dibenzothiophene group, a benzofuranylgroup, a phenanthroline group, a thiazolyl group, an isoxazolyl group,an oxadiazolyl group, a thiadiazolyl group, a benzothiazolyl group, aphenothiazinyl group, a dibenzofuranyl group, and the like, but are notlimited thereto.

In the present specification, the aliphatic ring may be an aliphatichydrocarbon ring or an aliphatic hetero ring, and may be monocyclic orpolycyclic. Examples of the aliphatic ring include a cyclopentyl group,a cyclohexyl group, and the like, and are not limited thereto.

In the present specification, examples of the organic group include analkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group,an aryl group, an aralkyl group, and the like. The organic group mayinclude a bond or a substituent other than a hydrocarbon group such as aheteroatom in the organic group. Further, the organic group may be anyone of a straight organic group, a branched organic group, and a cyclicorganic group.

In the present specification, the trivalent organic group means atrivalent group having three bonding positions in an organic compound.

Further, the organic group may also form a cyclic structure, and mayform a bond by including a heteroatom as long as the effects of theinvention are not impaired.

Specifically, examples thereof include a bond including a heteroatomsuch as an oxygen atom, a nitrogen atom, and a silicon atom. Specificexamples thereof include an ether bond, a thioether bond, a carbonylbond, a thiocarbonyl bond, an ester bond, an amide bond, a urethanebond, an imino bond (—N═C(-A)-, —C(═NA)-: A represents a hydrogen atomor an organic group), a carbonate bond, a sulfonyl bond, a sulfinylbond, an azo bond, and the like, and are not limited thereto.

The cyclic structure may be the aromatic ring, the aliphatic ring, andthe like as described above, and may be monocyclic or polycyclic.

In the present specification, the alkyl group may be straight orbranched, and the number of carbon atoms thereof is not particularlylimited, but is preferably 1 to 50. Specific examples thereof include amethyl group, an ethyl group, a propyl group, an isopropyl group, abutyl group, a t-butyl group, a pentyl group, a hexyl group, a heptylgroup, and the like, but are not limited thereto.

In the present specification, the alkenyl group may be straight orbranched, and the number of carbon atoms thereof is not particularlylimited, but is preferably 2 to 40. Specific examples thereof includevinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl,1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1-butenyl, 1,3-butadienyl,allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl,2-phenyl-2-(naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl,a stilbenyl group, a styrenyl group, and the like, but are not limitedthereto.

In the present specification, the cycloalkyl group is not limitedthereto, but has preferably 3 to 60 carbon atoms, and examples thereofinclude a cyclopentyl group, a cyclohexyl group, and the like, but arenot limited thereto.

In an exemplary embodiment of the present specification, 1 is 3 or more.

In an exemplary embodiment of the present specification, X is S.

In another exemplary embodiment, X is a haloalkyl group.

In another exemplary embodiment of the present specification, X is NR.

In an exemplary embodiment of the present specification, Y1 and Y2 arethe same as or different from each other, and are each independently ahalogen-substituted aromatic ring.

In an exemplary embodiment of the present specification, Y1 and Y2 arethe same as or different from each other, and are each independently afluorine-substituted aromatic hydrocarbon ring.

In an exemplary embodiment of the present specification, Y1 and Y2 arethe same as or different from each other, and are each independentlyNRR.

In another exemplary embodiment, Y1 and Y2 are each afluorine-substituted phenyl group. Specific examples thereof include2,4-phenyl, 2,6-phenyl, 2,3-phenyl, 3,4-phenyl, and the like, and arenot limited thereto.

In an exemplary embodiment of the present specification, the compoundrepresented by Chemical Formula 4 may be represented by any one of thefollowing structures.

In the structures, X, 1, and R are the same as those defined in ChemicalFormula 4.

According to an exemplary embodiment of the present specification, Z inChemical Formula 5 may be represented by any one of the followingChemical Formulae 5-1 to 5-4.

In Chemical Formulae 5-1 to 5-4,

L2 to L8 are the same as or different from each other, and are eachindependently a direct bond; —S—; —O—; —CO—; or —SO₂—,

R10 to R20 are the same as or different from each other, and are eachindependently hydrogen; deuterium; a halogen group; a cyano group; anitrile group; a nitro group; a hydroxy group; a substituted orunsubstituted alkyl group; a substituted or unsubstituted cycloalkylgroup; a substituted or unsubstituted alkoxy group; a substituted orunsubstituted alkenyl group; a substituted or unsubstituted aryl group;or a substituted or unsubstituted heteroaryl group,

a, b, c, f, h, i, and j are each an integer from 1 to 4,

d, e, and g are each an integer from 1 to 3,

k is an integer from 1 to 6,

when a, b, c, d, e, f, g, h, i, j, and k are each an integer of 2 ormore, two or more structures in the parenthesis are the same as ordifferent from each other.

In an exemplary embodiment of the present specification, L1 is CO.

In another exemplary embodiment, L1 is SO₂.

In still another exemplary embodiment, L1 is S.

In yet another exemplary embodiment, L2 is CO.

In still yet another exemplary embodiment, L2 is SO₂.

In a further exemplary embodiment, L2 is S.

In an exemplary embodiment of the present specification, L3 is CO.

In another exemplary embodiment, L3 is SO₂.

In still another exemplary embodiment, L3 is S.

In an exemplary embodiment of the present specification, L4 is CO.

In another exemplary embodiment, L4 is SO₂.

In an exemplary embodiment of the present specification, L5 is a directbond.

In another exemplary embodiment, L6 is a direct bond.

In an exemplary embodiment of the present specification, L7 is a directbond.

In an exemplary embodiment of the present specification, R10 to R20 arehydrogen.

In an exemplary embodiment of the present specification, R16 is ahalogen group.

In another exemplary embodiment, R16 is fluorine.

Further, in an exemplary embodiment of the present specification, thebrancher represented by Chemical Formula 5 may be represented by any oneof the following structures.

In an exemplary embodiment of the present specification, the polymer hasa weight average molecular weight of 500 g/mol to 2,000,000 g/mol. Whenthe polymer has a weight average molecular weight within the range,mechanical properties of an electrolyte membrane including the polymerdo not deteriorate, and the electrolyte membrane may be easilymanufactured by maintaining an appropriate solubility of the polymer.

In an exemplary embodiment of the present specification, the firstmonomer represented by Chemical Formula 1; and a second monomer which isdifferent from the first monomer and has at least one sulfonic acidgroup may constitute a random polymer.

In this case, a polymer including a monomer represented by ChemicalFormula 1 may easily form an ion channel because the structure of—[CR1R2]_(n)-A in the chemical formula spreads out in the form of apendant, so that A functional groups in the polymer are collected tofacilitate the phase separation. Accordingly, it is possible to expectan effect in that the ion conductivity of the polymer electrolytemembrane is improved.

In an exemplary embodiment of the present specification, the content ofthe first monomer represented by Chemical Formula 1 in the polymer is 1mol % to 99 mol % based on the total content of the polymer, and thecontent of a second monomer which is different from the first monomerand has at least one sulfonic acid group is 1 mol % to 99 mol % based onthe total content of the polymer. In an exemplary embodiment of thepresent specification, the content of the first monomer represented byChemical Formula 1 in the polymer is 50 mol % to 99 mol % based on thetotal content of the polymer, and the content of a second monomer whichis different from the first monomer and has at least one sulfonic acidgroup is 1 mol % to 50 mol % based on the total content of the polymer.

In an exemplary embodiment of the present specification, a polymerincluding: the first monomer represented by Chemical Formula 1; and asecond monomer which is different from the first monomer and has atleast one sulfonic acid group is a random polymer.

In another exemplary embodiment of the present specification, thepolymer is a block polymer including a hydrophilic block and ahydrophobic block, in which the hydrophilic block includes the firstmonomer represented by Chemical Formula 1.

In an exemplary embodiment of the present specification, the hydrophilicblock includes the first monomer represented by Chemical Formula 1 and asecond monomer having at least one sulfonic acid group.

In an exemplary embodiment of the present specification, in thehydrophilic block, the content of the first monomer is 1 mol % to 99 mol% based on the total content of the polymer, and the content of a secondmonomer which is different from the first monomer and has at least onesulfonic acid group is 1 mol % to 99 mol % based on the total content ofthe polymer. In an exemplary embodiment of the present specification, inthe hydrophilic block, the content of the first monomer represented byChemical Formula 1 is 50 mol % to 99 mol % based on the total content ofthe polymer, and the content of a second monomer which is different fromthe first monomer and has at least one sulfonic acid group is 1 mol % to50 mol % based on the total content of the polymer.

In an exemplary embodiment of the present specification, the hydrophilicblock and the hydrophobic block in the block polymer are included at amolar ratio of 1:0.1 to 1:10. In an exemplary embodiment of the presentspecification, the hydrophilic block and the hydrophobic block in theblock polymer are included at a molar ratio of 1:0.1 to 1:2. In anotherexemplary embodiment, the hydrophilic block and the hydrophobic block inthe block polymer are included at a molar ratio of 1:0.8 to 1:1.2. Inthis case, the ion transport capability of the block polymer may beincreased.

In an exemplary embodiment of the present specification, the monomerrepresented by Chemical Formula 1 in the hydrophilic block is includedin an amount of 0.01 mol % to 100 mol % based on the hydrophilic block.

In one exemplary embodiment of the present specification, thehydrophilic block has a number average molecular weight of 1,000 g/molto 300,000 g/mol. In a specific exemplary embodiment, the hydrophobicblock has a number average molecular weight of 2,000 g/mol to 100,000g/mol. In another exemplary embodiment, the hydrophobic block has anumber average molecular weight of 2,500 g/mol to 50,000 g/mol.

In one exemplary embodiment of the present specification, thehydrophobic block has a number average molecular weight of 1,000 g/molto 300,000 g/mol. In a specific exemplary embodiment, the hydrophobicblock has a number average molecular weight of 2,000 g/mol to 100,000g/mol. In another exemplary embodiment, the hydrophobic block has anumber average molecular weight of 2,500 g/mol to 50,000 g/mol.

According to an exemplary embodiment of the present specification, inthe case of a block polymer, the phase separation is facilitated due tothe clear division of the fractions of the hydrophilic block and thehydrophobic block, and as a result, the ions may be easily transported.According to an exemplary embodiment of the present specification, whenthe monomer represented by Chemical Formula 1 is included, the iontransport effect may be better than that of the polymer in the relatedart because the hydrophilic block and the hydrophobic block are moreclearly divided.

The block polymer means a polymer which is configured as one block andone or two or more blocks, which are different from the block, are eachlinked to a main chain of the polymer.

In an exemplary embodiment of the present specification, the blockpolymer may include a hydrophilic block and a hydrophobic block.Specifically, in one exemplary embodiment, the block polymer may includea hydrophilic block and a hydrophobic block, which include the monomerrepresented by Chemical Formula 1.

The “hydrophilic block” of the present specification means a blockhaving an ion exchange group as a functional group. Here, the functionalgroup may be any one selected from the group consisting of —SO₃H, —SO₃⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂, —PO₃H⁻M⁺, and —PO₃ ²⁻2M⁺. Here, M may be ametallic element. That is, the functional group may be hydrophilic.

The “block having an ion exchange group” of the present specificationmeans a block having 0.5 or more ion exchange groups on average when thenumber of ion exchange groups is represented by the number of ionexchange groups per structural monomer constituting the correspondingblock, and is more preferably a block having 1.0 or more ion exchangegroups on average per structural monomer.

“A hydrophobic block” of the present specification means a polymer blocksubstantially having no ion exchange group.

The “block substantially having no ion exchange group” of the presentspecification means a block having less than 0.01 ion exchange groups onaverage when the number of ion exchange groups is represented by thenumber of the ion exchange groups per structural monomer constitutingthe corresponding block, and is more preferably a block having 0.05 orless ion exchange groups on average, and even more preferably a blockhaving no ion exchange group.

Further, the present specification provides a polymer electrolytemembrane including the above-described polymer.

When the polymer electrolyte membrane includes a polymer including amonomer derived from the compound according to an exemplary embodimentof the present specification, the polymer electrolyte membrane may havehigh mechanical strength and high ion conductivity, and may facilitatethe phase separation phenomenon of the electrolyte membrane.

In the present specification, the “electrolyte membrane” is a membranewhich may exchange ions, and includes a membrane, an ion exchangemembrane, an ion transport membrane, an ion conductive membrane, aseparation membrane, an ion exchange separation membrane, an iontransport separation membrane, an ion conductive separation membrane, anion exchange electrolyte membrane, an ion transport electrolytemembrane, or an ion conductive electrolyte membrane, and the like.

The polymer electrolyte membrane according to an exemplary embodiment ofthe present specification may be manufactured by using materials and/ormethods known in the art, except that the polymer electrolyte membraneincludes a polymer including a monomer derived from the compound.

According to an exemplary embodiment of the present specification, thepolymer electrolyte membrane has ion conductivity of 0.01 S/cm or moreand 0.5 S/cm or less. In another exemplary embodiment, the polymerelectrolyte membrane has ion conductivity of 0.01 S/cm or more and 0.3S/cm or less.

In an exemplary embodiment of the present specification, the ionconductivity of the polymer electrolyte membrane may be measured underhumidified conditions. The humidified conditions in the presentspecification may mean a relative humidity (RH) of 10% to 100%.

Further, in an exemplary embodiment of the present specification, thepolymer electrolyte membrane has an ion exchange capacity (IEC) value of0.01 mmol/g to 5.0 mmol/g. When the polymer electrolyte membrane has theion exchange capacity (IEC) value within the range, ion channels areformed in the polymer electrolyte membrane, and the polymer may exhibition conductivity.

In an exemplary embodiment of the present specification, the polymerelectrolyte membrane has a thickness of 1 μm to 500 μm. The polymerelectrolyte membrane having a thickness within the range may reduce theelectric short and the crossover of the electrolyte material, and mayexhibit excellent cation conductivity characteristics.

An exemplary embodiment of the present specification provides areinforced membrane including: a substrate; and the above-describedpolymer.

In an exemplary embodiment of the present specification, the ‘reinforcedmembrane’ is an electrolyte membrane including a substrate, which is areinforced material, and may mean a membrane including a substrate, anion exchange membrane, an ion transport membrane, an ion conductivemembrane, a separation membrane, an ion exchange separation membrane, anion transport separation membrane, an ion conductive separationmembrane, an ion exchange electrolyte membrane, an ion transportelectrolyte membrane, or an ion conductive electrolyte membrane, and thelike, as a membrane capable of exchanging ions.

In the present specification, the substrate may mean a support having a3-D network structure, and a reinforced membrane including the substrateand the polymer may mean that the polymer is included in at least aportion of one surface of the substrate, a surface facing the onesurface, and a pore region in the substrate. That is, the reinforcedmembrane of the present specification may be provided in a form in whichthe polymer is impregnated in the substrate.

The polymer is the same as the contents as described above.

In the case of a hydrocarbon-based ion transport separation membrane,there is a problem in that the ion transport capability deteriorates ascompared to a fluorine-based separation membrane, and the chemicalresistance is weak. Accordingly, the reinforced membrane according to anexemplary embodiment of the present specification includes a polymerincluding the unit represented by Chemical Formula 1, and thus has highmechanical strength and high ion conductivity, and may facilitate thephase separation phenomenon of the reinforced membrane.

Further, the reinforced membrane according to an exemplary embodiment ofthe present specification includes a substrate, and thus enhanceschemical resistance and durability, thereby improving the service lifeof the device.

In an exemplary embodiment of the present specification, as thesubstrate, one or two is or are selected from the group consisting ofpolypropylene (PP), polytetrafluoroethylene (PTFE), polyethylene (PE),and polyvinylidene difluoride (PVDF).

In an exemplary embodiment of the present specification, the content ofthe polymer is 10 parts by weight to 99 parts by weight based on 100parts by weight of the reinforced membrane.

In another exemplary embodiment, based on 100 parts by weight of thereinforced membrane, the content of the polymer is 10 parts by weight to99 parts by weight, and the content of the substrate is 1 part by weightto 90 parts by weight. As the content of the substrate is increased, thecrossover of vanadium ions may be decreased, and as the content of thepolymer is increased, the performance of the battery may be improved.

Accordingly, when the contents of the substrate and the polymeraccording to an exemplary embodiment of the present specification arewithin the range, the performance of the battery may be maintained, andsimultaneously, the crossover of vanadium ions may be decreased.

According to an exemplary embodiment of the present specification, thereinforced membrane has ion conductivity of 0.001 S/cm or more and 0.5S/cm or less. In another exemplary embodiment, the reinforced membranehas ion conductivity of 0.001 S/cm or more and 0.3 S/cm or less.

In the present specification, the ion conductivity may be measured underthe same conditions as the above-described method.

Further, in an exemplary embodiment of the present specification, thereinforced membrane has an ion exchange capacity (IEC) value of 0.01mmol/g to 5.0 mmol/g. When the reinforced membrane has the ion exchangecapacity (IEC) value within the range, ion channels are formed in thereinforced membrane, and the polymer may exhibit ion conductivity.

In an exemplary embodiment of the present specification, the reinforcedmembrane has a thickness of 0.01 μm to 10,000 μm. The reinforcedmembrane having a thickness within the range may reduce the electricshort and the crossover of the electrolyte material, and may exhibitexcellent cation conductivity characteristics.

The present specification also provides a method for manufacturing areinforced membrane, the method including: preparing a substrate; andimpregnating the substrate in a polymer including the unit representedby Chemical Formula 1.

In the present specification, the impregnation means that a polymerpermeates into a substrate. In the present specification, theimpregnation may be carried out by using dipping of the substrate in thepolymer, a slot dye coating, a bar casting, and the like.

In the present specification, the dipping may be expressed as a termsuch as dip coating or a dipping method.

In an exemplary embodiment of the present specification, the reinforcedmembrane may have an orientation. Specifically, in an exemplaryembodiment of the present specification, the substrate may bemanufactured through uniaxial stretching or biaxial stretching, and theorientation of a substrate by the stretching may determine theorientation of the reinforced membrane. Therefore, the reinforcedmembrane according to an exemplary embodiment of the presentspecification may have an orientation of a machine direction (MD) and adirection perpendicular to the machine direction (MD), and thereinforced membrane may exhibit the difference in physical propertiessuch as stress and elongation according to the orientation.

The present specification also provides a method for manufacturing areinforced membrane, the method including: preparing a substrate; anddipping the substrate in the polymer.

In the present specification, the substrate and the polymer are the sameas those as described above.

The present specification also provides a membrane-electrode assemblyincluding: an anode; a cathode; and the above-described polymerelectrolyte membrane disposed between the anode and the cathode.

The present specification also provides a membrane-electrode assemblyincluding: an anode; a cathode; and the above-described reinforcedmembrane disposed between the anode and the cathode.

The membrane-electrode assembly (MEA) means an assembly of electrodes (acathode and an anode) in which an electrochemical catalyst reaction offuel and air occurs and a polymer membrane in which hydrogen ions aretransported, and is a single integral-type unit in which electrodes (acathode and an anode) and an electrolyte membrane are adhered.

The membrane-electrode assembly of the present specification is in theform in which a catalyst layer of an anode and a catalyst layer of acathode are brought into contact with an electrolyte membrane, and maybe manufactured by a typical method known in the art. As an example, themembrane-electrode assembly may be manufactured by thermallycompressing, at 100° C. to 400° C., the cathode; the anode; and theelectrolyte membrane positioned between the cathode and the anode in astate in which the cathode, the anode, and the electrolyte membrane arebrought into close contact with each other.

An anode electrode may include an anode catalyst layer and an anode gasdiffusion layer. The anode gas diffusion layer may include an anodemicro porous layer and an anode electrode substrate.

A cathode electrode may include a cathode catalyst layer and a cathodegas diffusion layer. The cathode gas diffusion layer may include acathode micro porous layer and a cathode electrode substrate.

FIG. 1 schematically illustrates the electricity generation principle ofa fuel cell, and in the fuel cell, the most fundamental unit ofgenerating electricity is a membrane-electrode assembly (MEA), and themembrane-electrode assembly is composed of an electrolyte membrane 100and electrodes of an anode 200 a and a cathode 200 b formed on bothsurfaces of the electrolyte membrane 100. Referring to FIG. 1 whichillustrates the elasticity generation principle of a fuel cell, anoxidation reaction of a fuel such as hydrogen or a hydrocarbon such asmethanol and butane occurs in the anode 200 a, and as a result, hydrogenions (H⁺) and electrons (e⁻) are generated, and the hydrogen ions moveto the cathode 200 b through the electrolyte membrane 100. In thecathode 200 b, hydrogen ions transported through the electrolytemembrane 100, an oxidizing agent such as oxygen, and electrons arereacted to produce water. Electrons move to an external circuit by thereaction.

The catalyst layer of the anode electrode is a site where an oxidationreaction of fuel occurs, and it is possible to preferably use a catalystselected from the group consisting of platinum, ruthenium, osmium, aplatinum-ruthenium alloy, a platinum-osmium alloy, a platinum-palladiumalloy, and a platinum-transition metal alloy. The catalyst layer of thecathode electrode is a site where a reduction reaction of an oxidizingagent occurs, and platinum or a platinum-transition metal alloy may bepreferably used as a catalyst. The catalysts may be not only used asthey are, but also used while being supported on a carbon-based carrier.

The process of introducing a catalyst layer may be carried out by atypical method known in the art, and for example, a catalyst layer maybe formed by directly coating an electrolyte membrane with a catalystink or coating a gas diffusion layer with a catalyst ink. In this case,the method of coating a catalyst ink is not particularly limited, but itis possible to use a method such as spray coating, tape casting, screenprinting, blade coating, die coating or spin coating, and the like. Thecatalyst ink may be representatively composed of a catalyst, a polymerionomer, and a solvent.

The gas diffusion layer serves as both a current conductor and a channelthrough which reaction gasses and water move, and has a porousstructure. Accordingly, the gas diffusion layer may include a conductivesubstrate. As the conductive substrate, carbon paper, carbon cloth, orcarbon felt may be preferably used. The gas diffusion layer may furtherinclude a micro porous layer between the catalyst layer and theconductive substrate. The micro porous layer may be used in order toimprove the performance of a fuel cell under low humidified conditions,and serves to allow an electrolyte membrane to be maintained in asufficiently wet state by reducing the amount of water leaving out ofthe gas diffusion layer.

An exemplary embodiment of the present specification provides a polymerelectrolyte-type fuel cell including: two or more membrane-electrodeassemblies; a stack which includes a bipolar plate disposed between themembrane-electrode assemblies; a fuel supplying part which supplies fuelto the stack; and an oxidizing agent supplying part which supplies anoxidizing agent to the stack.

In the present specification, the membrane-electrode assembly includesthe above-described polymer electrolyte membrane, or includes areinforced membrane.

A fuel cell is an energy conversion device that converts chemical energyof a fuel directly into electrical energy. That is, the fuel cell uses afuel gas and an oxidizing agent, and adopts a method of producingelectric power by using electrons generated during the redox reaction ofthe fuel gas and the oxidizing agent.

The fuel cell may be manufactured by a typical method known in the artby using the above-described membrane-electrode assembly (MEA). Forexample, the fuel cell may be manufactured by being composed of themembrane-electrode assembly manufactured above and the bipolar plate.

The fuel cell of the present specification includes a stack, a fuelsupplying part, and an oxidizing agent supplying part.

FIG. 3 schematically illustrates the structure of a fuel cell, and thefuel cell includes a stack 60, an oxidizing agent supplying part 70, anda fuel supplying part 80.

The stack 60 includes the aforementioned one or two or moremembrane-electrode assemblies, and when two or more membrane-electrodeassemblies are included, the stack 60 includes a separator interposedtherebetween. The separator serves to prevent the membrane-electrodeassemblies from being electrically connected to each other, and totransport fuel and an oxidizing agent supplied from the outside to themembrane-electrode assemblies.

The oxidizing agent supplying part 70 serves to supply an oxidizingagent to the stack 60. As the oxidizing agent, oxygen isrepresentatively used, and oxygen or air may be used by being injectedby means of a pump 70.

The fuel supplying part 80 serves to supply fuel to the stack 60, andmay be composed of a fuel tank 81 which stores fuel and a pump 82 whichsupplies fuel stored in the fuel tank 81 to the stack 60. As the fuel,hydrogen or hydrocarbon fuel in a gas or liquid state may be used.Examples of the hydrocarbon fuel include methanol, ethanol, propanol,butanol, or natural gases.

The fuel cell can be a polymer electrolyte fuel cell, a direct liquidfuel cell, a direct methanol fuel cell, a direct formic acid fuel cell,a direct ethanol fuel cell, or a direct dimethyl ether fuel cell, andthe like.

When the electrolyte membrane according to an exemplary embodiment ofthe present specification is used as an ion exchange membrane of a fuelcell, the above-described effect may be exhibited.

Further, an exemplary embodiment of the present specification provides aredox flow battery including: a positive electrode cell including apositive electrode and a positive electrode electrolytic solution; anegative electrode cell including a negative electrode and a negativeelectrode electrolytic solution; and the polymer electrolyte membraneaccording to an exemplary embodiment of the present specification, whichis disposed between the positive electrode cell and the negativeelectrode cell.

Another exemplary embodiment provides a redox flow battery including: apositive electrode cell including a positive electrode and a positiveelectrode electrolytic solution; a negative electrode cell including anegative electrode and a negative electrode electrolytic solution; andthe reinforced membrane according to an exemplary embodiment of thepresent specification, which is disposed between the positive electrodecell and the negative electrode cell.

A redox flow battery (oxidation-reduction flow battery) is anelectrochemical power storage device that stores chemical energy of anactive material directly into electrical energy by using a system inwhich the active material included in an electrolytic solution isoxidized and reduced and thus the battery is charged and discharged. Theredox flow battery uses a principle in which when electrolytic solutionsincluding active materials having different oxidation states meet eachother with an ion exchange membrane interposed therebetween, electronsare given and received, and thus the battery is charged and discharged.In general, the redox flow battery is composed of a tank which containsan electrolytic solution, a battery cell in which the charge anddischarge occur, and a circulation pump which circulates theelectrolytic solution between the tank and the battery cell, and theunit cell of the battery cell includes an electrode, an electrolyte, andan ion exchange membrane.

When the electrolyte membrane according to an exemplary embodiment ofthe present specification is used as an ion exchange membrane of a redoxflow battery, the above-described effect may be exhibited.

The redox flow battery of the present specification may be manufacturedby a typical method known in the art, except that the redox flow batteryincludes the polymer electrolyte membrane according to an exemplaryembodiment of the present specification.

As illustrated in FIG. 2, the redox flow battery is divided into apositive electrode cell 32 and a negative electrode cell 33 by anelectrolyte membrane 31. The positive electrode cell 32 and the negativeelectrode cell 33 include a positive electrode and a negative electrode,respectively. The positive electrode cell 32 is connected to a positiveelectrode tank 10 for supplying and releasing a positive electrodeelectrolytic solution 41 through pipes. The negative electrode cell 33is also connected to a negative electrode tank 20 for supplying andreleasing a negative electrode electrolytic solution 42 through pipes.The electrolytic solution is circulated through pumps 11 and 21, and anoxidation/reduction reaction (that is, a redox reaction) in which theoxidation number of ions is changed occurs, and as a result, the chargeand discharge occur in the positive electrode and the negativeelectrode.

MODE FOR INVENTION

Hereinafter, the present specification will be described in detail withreference to Examples for specifically describing the presentspecification. However, the Examples according to the presentspecification may be modified in various forms, and it is notinterpreted that the scope of the present specification is limited tothe Examples described below in detail. The Examples of the presentspecification are provided to more completely explain the presentspecification to a person with ordinary skill in the art.

Example 1

Potassium carbonate (K₂CO₃)(5.5 g) and bisphenol (1.86 g) were put into2-((2,4-difluorophenyl)thio)-1,1,2,2-tetrafluoroethane-1-sulfonic acid(3 g) and 2-fluoro-5-((4-fluorophenyl) sulfonyl)benzenesulfonic acid(0.5 g), N-methylpyrrolidone (NMP) and benzene were put thereinto, andthe resulting mixture was stirred at 140° C. for 4 hours. Thereafter,the temperature was increased to 180° C., and a reaction was carried outfor 24 hours to obtain a polymer.

Comparative Example 1

A polymer in Comparative Example 1 was synthesized in the same manner asin the Preparation Example, except that the aforementioned monomer wasused instead of the monomer used in the Preparation Example.

The results of measuring the ion conductivities of the polymermanufactured in Example 1 and Comparative Example 1 are shown in Table1.

TABLE 1 Comparative Example 1 Example 1 Ion conductivity (S/cm) 0.040.11

As a result of Table 1, it can be confirmed that the polymer includingboth the first monomer and the second monomer has high ion conductivity.

Comparative Example 2

As a result of carrying out an experiment of obtaining a polymer byusing a 2,4-difluoro partial fluorine-based monomer, which is a firstmonomer represented by Chemical Formula 1-1 in Example 1, it wassuccessful in obtaining a polymer having a high molecular weight.However, it was attempted to prepare a polymer by using a 2,5-difluoropartial fluorine-based monomer generally used, but it failed to obtain apolymer having a high molecular weight under the same conditions. Themolecular weight of the polymer was measured by gel permeationchromatography (GPC), and is shown in the following Table 2.

Comparative Example 3

It was attempted to prepare a polymer by using a monomer, which is SO₂,instead of the —[CR1R2]_(n)-A structure and an S atom as a linker of thebenzene ring in Chemical Formula 1 in the same manner as in ComparativeExample 1, but it failed to obtain a polymer having a high molecularweight under the same conditions. The molecular weight of the polymerwas measured by gel permeation chromatography (GPC), and is shown in thefollowing Table 2.

TABLE 2 Partial fluorine-based membrane Mn (g/mol) Mw (g/mol) Mw/MnExample 1 84,000 622,000 7.40 Comparative Example 2 N/A N/A N/AComparative Example 3 N/A N/A N/A

In Table 2, N/A means not available, and it can be confirmed that thepolymer was not formed.

As a result of Example 1 and Comparative Example 2, the monomer with thefunctional groups substituted at 2 and 5 positions, which is generallyused in the art, has been commercially used without consideringreactivity in spite of a big difference in reactivity during thepolymerization reaction according to the properties of the functionalgroup substituted at the other positions.

In a 2,4-difluoro halogenated compound according to an exemplaryembodiment of the present specification, it can be confirmed that thefunctional group of Chemical Formula 2 hung as a pendant exhibitproperties of an electron withdrawer as a whole, and accordingly,reactivity during the polymerization reaction is greatly improved, andas a result, the compound has an advantage in obtaining a polymer havinga high molecular weight.

From the results of Example 1 and Comparative Example 3, it can beconfirmed that a compound including the monomer represented by ChemicalFormula 1 according to an exemplary embodiment of the presentspecification is chemically stable, and thus easily forms the polymer.

1. A polymer comprising: a first monomer represented by the followingChemical Formula 1; and a second monomer which is different from thefirst monomer and has at least one sulfonic acid group:

in Chemical Formula 1, A is —SO₃H, —SO₃ ⁻M⁺, —COOH, —COO⁻M⁺, —PO₃H₂,—PO₃H⁻M⁺, —PO₃ ²⁻2M⁺, —O(CF₂)_(m)SO₃H, —O(CF₂)_(m)SO₃ ⁻M⁺,—O(CF₂)_(m)COOH, —O(CF₂)_(m)COO⁻M⁺, —O(CF₂)_(m)PO₃H₂,—O(CF₂)_(m)PO₃H⁻M⁺, or —O(CF₂)_(m)PO₃ ²⁻2M⁺, m is an integer from 1 to6, M is a Group 1 element, R1 and R2 are the same as or different fromeach other, and are each independently a halogen group, n is an integerfrom 1 to 10, and when m and n are 2 or more, two or more structures inthe parenthesis are the same as or different from each other. 2.(canceled)
 3. The polymer of claim 1, wherein the first monomerrepresented by Chemical Formula 1 is represented by any one of thefollowing Chemical Formulae 1-1 to 1-9:


4. The polymer of claim 1, wherein the second monomer is derived from acompound represented by the following Chemical Formula 2 or ChemicalFormula 3:

in Chemical Formulae 2 and 3, A1 to A4 are the same as or different fromeach other, and are each independently a hydroxy group; or a halogengroup, L1 is a direct bond; CR3R4; C═O; O; S; SO₂; SiR5R6; or asubstituted or unsubstituted fluorenylene group, R3 to R6 are the sameas or different from each other, and are each independently hydrogen; analkyl group; fluorine; a haloalkyl group; or a phenyl group, S1 to S3are the same as or different from each other, and are each independentlyhydrogen; deuterium; a halogen group; a cyano group; a nitrile group; anitro group; a hydroxy group; a haloalkyl group; a sulfonic acid group;a substituted or unsubstituted alkyl group; a substituted orunsubstituted cycloalkyl group; a substituted or unsubstituted alkoxygroup; a substituted or unsubstituted alkenyl group; a substituted orunsubstituted silyl group; a substituted or unsubstituted aryl group; ora substituted or unsubstituted heterocyclic group, s1, s2, and s3 areeach an integer from 1 to 4, m′ is an integer from 1 to 5, when s1, s2,s3, and m′ are each an integer of 2 or more, two or more structures inthe parenthesis are the same as or different from each other, andChemical Formula 2 and Chemical Formula 3 are substituted with at leastone sulfonic acid group.
 5. The polymer of claim 1, wherein the secondmonomer is derived from a compound represented by any one of thefollowing Chemical Formulae 2-1 to 2-4, 3-1, and 3-2:

in Chemical Formulae 2-2, 2-4, and 3-2, A1′ and A2′ are the same as ordifferent from each other, and are each independently a halogen group.6. The polymer of claim 1, wherein the polymer comprises a brancherderived from a compound represented by the following Chemical Formula 4or a brancher represented by the following Chemical Formula 5:

in Chemical Formulae 4 and 5, X is S; O; CO; SO; SO₂; NR; and ahydrocarbon-based or fluorine-based binder, l is an integer from 0 to100, when l is 2 or more, two or more X's are the same as or differentfrom each other, Y1 and Y2 are the same as or different from each other,and are each independently NRR; an aromatic ring which is once or twiceor more substituted with a substituent selected from the groupconsisting of a hydroxy group and a halogen group; or an aliphatic ringwhich is once or twice or more substituted with a substituent selectedfrom the group consisting of a hydroxy group and a halogen group, R isan aromatic ring substituted with a halogen group; or an aliphatic ringsubstituted with a halogen group, and Z is a trivalent organic group. 7.The polymer of claim 6, wherein the brancher represented by ChemicalFormula 5 is any one of the following structures:


8. The polymer of claim 1, wherein the polymer has a weight averagemolecular weight of 500 g/mol to 2,000,000 g/mol.
 9. The polymer ofclaim 1, wherein the polymer is a random polymer.
 10. The polymer ofclaim 1, wherein the polymer comprises a hydrophilic block and ahydrophobic block, and the hydrophilic block is a block polymercomprising the first monomer represented by Chemical Formula
 1. 11. Thepolymer of claim 10, wherein the hydrophilic block and the hydrophobicblock in the block polymer are comprised at a molar ratio of 1:0.1 to1:10.
 12. A polymer electrolyte membrane comprising the polymeraccording to claim
 1. 13. A reinforced membrane comprising: a substrate;and the polymer according to claim
 1. 14. The polymer electrolytemembrane of claim 12, wherein the polymer electrolyte membrane has ionconductivity of 0.01 S/cm to 0.5 S/cm.
 15. The polymer electrolytemembrane of claim 12, wherein the polymer electrolyte membrane has anion exchange capacity (IEC) value of 0.01 mmol/g to 5 mmol/g.
 16. Amembrane-electrode assembly comprising: an anode; a cathode; and thepolymer electrolyte membrane of claim 12 disposed between the anode andthe cathode.
 17. A polymer electrolyte-type fuel cell comprising: thetwo or more membrane-electrode assemblies according to claim 16; a stackwhich comprises a bipolar plate disposed between the membrane-electrodeassemblies; a fuel supplying part which supplies fuel to the stack; andan oxidizing agent supplying part which supplies an oxidizing agent tothe stack.
 18. A redox flow battery comprising: a positive electrodecell comprising a positive electrode and a positive electrodeelectrolytic solution; a negative electrode cell comprising a negativeelectrode and a negative electrode electrolytic solution; and thepolymer electrolyte membrane of claim 12 disposed between the positiveelectrode cell and the negative electrode cell.
 19. A membrane-electrodeassembly comprising: an anode; a cathode; and the reinforced membrane ofclaim 13 disposed between the anode and the cathode.
 20. A polymerelectrolyte-type fuel cell comprising: the two or moremembrane-electrode assemblies according to claim 19; a stack whichcomprises a bipolar plate disposed between the membrane-electrodeassemblies; a fuel supplying part which supplies fuel to the stack; andan oxidizing agent supplying part which supplies an oxidizing agent tothe stack.
 21. A redox flow battery comprising: a positive electrodecell comprising a positive electrode and a positive electrodeelectrolytic solution; a negative electrode cell comprising a negativeelectrode and a negative electrode electrolytic solution; and thereinforced membrane of claim 13 disposed between the positive electrodecell and the negative electrode cell.